Charles River Ventures (CRV), a venture capital firm that focuses on mobile, Internet, and software startups, closed its fifteenth fund of $375 million today.

“We expected this funding raising to be tough given the current environment, and we were surprised by the demand from current investors,” CRV general partner Izhar Armony told VentureBeat in an interview.

The fund was originally set for $300 million, but investors offered well beyond that in just over two month’s time. The VC had to turn investors away in order to keep the fund focused and small.

“Half of our funding goes into consumer web and mobile categories and 30 to 40 percent goes towards enterprise startups. We also have our X-factor companies that are off the beaten track and include hard sciences, energy projects, and robotics,” Izhar Armony told VentureBeat in an interview.

CRV’s portfolio consists of a few well-known tech startups including Twitter, Yammer, Vlingo, and Carrier IQ. Some of its more recent exits include the IPOs of RPX Corporation, Broadsoft, and The Active Network, which the VC notes have collectively generated more than $2.6 billion in market cap. CRV also had two notable acquisitions deals last year; Cisco’s purchase of BNI Video and Nuance Communications’ pending acquisition of Vlingo.

The 42-year-old company will continue to invest in early-stage Web startups. CRV is also interested in investing in mobile companies, which it feels are taking off more now than ever.

“It’s been very interesting to see how the mobile device is becoming the central part of you life, for example, no one has alarm clocks anymore — you just use your phone,” Armony told me.

CRV is a bi-coastal firm with offices in Menlo Park, Calif. and Cambridge, Mass. The firm was founded in 1970 and has a team of 10 investment partners.